Question 390284
Distance(d) equals Rate(r) times Time(t) or d=rt;  r=d/t and t=d/r
Let r=rate (speed) of plane in still air
And let w=speed of the wind

r-w=445  against wind, subtract wind speed.-----eq1
r+w=515  with wind, add wind speed----eq2

add eq1 and eq2 and we get:
2r=960
r=480----speed of plane in still air


Hope this helps--ptaylor